A system of circumferentially-sensitive miniature transducers, which should allow more accurate esophageal manometry than is provided by other systems, will be developed and evaluated by simultaneous comparison with a perfused catheter system. The transducer system will be applied to systematic study of the relationships in normal man between age, sex and esophageal function. Normal subjects will range in age between 21 and 90, and will be examined also by a standard cineradiographic technique. The information from this study will provide reliable values for the normal limits of human esophageal function, with due regard for sex and age-related changes, and hence an adequate data base for the recognition of significant deviation from normality. In addition, control of gastroesophageal sphincteric competence will be investigated by manometric study of the effects of pentagastrin, of secretin, and of increased intraabdominal pressure, with particular emphasis on the interrelationships between these factors, in normal subjects and in patients with reflux esophagitis. The reproducibility of sphincteric responses to these influences will be determined by repeated studies in normal subjects; and the possibility that the success of hiatal hernia repair is related to alterations in sphincteric reactivity will be evaluated by pre- and post-operative studies in patients with esophagitis. Finally, prospective information about the natural history of symptomatic diffuse spasm will be obtained by repeated standardized manometric studies, at six monthly intervals in patients with this disorder. The relationship between diffuse spasm and achalasia will be explored by investigation of sphincteric and distal esophageal responses to pentagastrin and to mecholyl, with coincident examination of sphincteric deglutitive behavior, in patients with diffuse spasm.